1. Field of the Invention
The present invention relates to image formation apparatuses, and more particularly, to an image formation apparatus having a printout portion of a plurality of formats.
2. Description of the Related Art
This application is based on Japanese Patent Application No. 9-030623 filed in Japan, the contents of which are hereby incorporated by reference.
Conventional ink jet printers have a piezoelectric element employed in the printer head. In this printer head, the ink in a predetermined closed cavity is pressurized by the deflection of a piezoelectric element driven by application of a voltage. The ink subjected to pressure is ejected towards a recording sheet in the form of an ink droplet through a nozzle hole provided in the predetermined closed cavity.
Some of these printer heads have nozzle holes of two different diameters. Ink droplets of a plurality of sizes can be ejected to realize representation of a half tone image smoothly and efficiently by the provision of nozzle holes with different diameters and by varying the level of the voltage for driving the piezoelectric element.
When an image absent of the half tone level is to be represented, for example when only characters are to be printed out on a recording sheet by the above-described printer head, the nozzle with the smaller diameter will not be used. Printing is carried out only through the nozzle having the greater diameter. This means that the efficiency is poor.
In view of the foregoing, an object of the present invention is to provide an image formation apparatus that can carry out printing efficiently to increase the printout speed.
According to an aspect of the present invention, an image formation apparatus includes a first printout portion for printing out a dot of a predetermined size, a second printout portion for printing out a dot of a size smaller than the predetermined size, and a controller for providing control so that a dot of a size substantially equal to the size of a dot formed by the first printout portion is printed out using the second printout portion.
According to another aspect of the present invention, a printout control method is characterized in that a dot of a size substantially equal to the size of a dot formed by the first printout portion is printed out using the second printout portion.
According to a further aspect of the present invention, a control device of an image formation apparatus is characterized by including a controller for providing control so as to carry out printing by said first printout portion as well as printing out a dot of size substantially equal to the size of a dot formed by the first printout portion using the second printout portion.
According to the present invention, an image formation apparatus can be provided that carries out printing efficiently to improve the printout speed.